Adoptive cancer immunotherapy involves isolation, ex vivo activation and expansion of immune cells, and subsequent injection into patients with cancer. Since Rosenberg et al first introduced adoptive immunotherapy for the treatment of human cancers (Rosenberg et al. 1985; Rosenberg et al. 1988), several types of immune cells, including lymphokine activated killer cells (LAK), CD8+ cytotoxic T lymphocytes (CTL), natural killer (NK) cells, NK T cells and tumor infiltrating lymphocytes (TIL) have been used in clinical trials (Verneris et al. 2002; Toh et al. 2005; Leemhuis et al. 2005; Yee et al. 2002; Dudley and Rosenberg 2003; Dudley et al. 2005). Currently the transfer of ex vivo activated and expanded autologous tumor specific CD8+ CTLs may induce objective clinical responses in significant number of patients (Gattinoni et al. 2005; Rosenberg, Yang, and Restifo 2004; Dudley and Rosenberg 2003; Childs and Barrett 2004; Riddell 2004; Yee et al. 2002) and are considered the most effective approach to immunotherapy (Pure, Allison, and Schreiber 2005). However, this treatment is severely limited by the need to identify relevant tumor antigens. Moreover, cancer relapse occurs even after repeated injections (Meidenbauer et al. 2003). This probably is because many of the in vitro cultured CTLs die within a few hours after adoptive transfer and most do not survive for more than a few days (Gattinoni et al. 2005; Riddell 2004; Speiser and Romero 2005; Zhang, Miller, and Zhang 1996; Khan et al. 1999). This approach can also result in severe autoimmune disease in treated patients (Dudley and Rosenberg 2003). Adoptive transfer of activated allogeneic lympocytes can mount effective anti-tumor responses, but the infused allogeneic cells can also attack host tissue and organs causing graft versus host disease (GVHD). Recent studies, including the inventors' work, have shown in both animal models and cancer patients that adoptive transfer of allogeneic lymphocytes recognizing either host minor histocompatibility antigens (MiHA) or single MHC class I antigens can mediate effective anti-tumor activities towards hematopoetic malignancies without causing GVHD (Young et al. 2003b; Perreault and Brochu 2002; Fontaine et al. 2001; Marijt et al. 2003). Because identifying a single class I, particularly a dominant MiHA that is present in patients but not in donors, is a difficult task, its clinical application to patients is complex. The current goal of adoptive cancer immunotherapy is to develop novel strategies allowing the generation of a large number of T cells that can persist and migrate to tumor sites, and effectively eliminate tumor cells without causing GVHD or autoimmune disease.
The majority of T cells in human peripheral blood express either CD4 or CD8 molecules. Approximately 1-3% of them express CD3 but lack CD4 and CD8 co-receptors. Based on the expression of the natural killer (NK) cell markers, these cells can be divided further into 2 subpopulations: NKT cells which express NK cell surface markers such as CD56 and CD16, and double negative (DN) cells which do not express these NK markers. Previously the inventors have demonstrated in mouse models that DN T cells express a unique set of cell surface markers and a cytokine profile that distinguishes them from previously described lymphocytes (Zhang et al. 2000). Unlike CD4 or CD8 T cells, infusion of in vitro activated allogeneic DN T cells did not cause GVHD. Furthermore, the injected allogeneic DN T cells can also prevent CD8 T cell-induced GVHD in recipients. Moreover, this treatment can prevent death in more than 75% of the recipients that were inoculated with a lethal dose of autologous A20 lymphoma cells either systemically or locally (Young et al. 2003b; Young et al. 2001).
Several studies have shown that autologous and syngeneic CD8+ T cells can be manipulated to induce anti-tumor responses (Lan et al. 2001; Dudley et al. 2002; Dudley and Rosenberg 2003). Although injection of allogeneic DN T cells does not appear to cause GVHD in mice (Young et al. 2003a), using autologous DN T cells that are activated by the patient's tumor antigens have following advantages over use of allogeneic T cells: 1) Injection of autologous cells does not have risk of causing GVHD or transmitting other disease; 2) They may allow induction of controlled and specific immune responses tailored for the individual cancer patient; 3) Autologous cells are easier to be applied to phase I and II clinical trails.
Human DN T cells were recently characterized. They display similar characteristics as those found in mouse DN T cells in terms of cell surface marker expression, cytokine profile, and mechanisms of action (Fischer et al. 2005; Zhang et al. 2000). However, the role of human DN T cells in tumor immunity has not been investigated previously due to the limited number of DN T cells that can be obtained.
In view of the foregoing, there is a need in the art to develop a method for expanding double negative T cells in culture.